Merge tag 'ieee802154-for-davem-2019-11-13' of git://git.kernel.org/pub/scm/linux...
[linux-2.6-microblaze.git] / drivers / md / dm-uevent.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Device Mapper Uevent Support (dm-uevent)
4  *
5  * Copyright IBM Corporation, 2007
6  *      Author: Mike Anderson <andmike@linux.vnet.ibm.com>
7  */
8 #include <linux/list.h>
9 #include <linux/slab.h>
10 #include <linux/kobject.h>
11 #include <linux/dm-ioctl.h>
12 #include <linux/export.h>
13
14 #include "dm.h"
15 #include "dm-uevent.h"
16
17 #define DM_MSG_PREFIX "uevent"
18
19 static const struct {
20         enum dm_uevent_type type;
21         enum kobject_action action;
22         char *name;
23 } _dm_uevent_type_names[] = {
24         {DM_UEVENT_PATH_FAILED, KOBJ_CHANGE, "PATH_FAILED"},
25         {DM_UEVENT_PATH_REINSTATED, KOBJ_CHANGE, "PATH_REINSTATED"},
26 };
27
28 static struct kmem_cache *_dm_event_cache;
29
30 struct dm_uevent {
31         struct mapped_device *md;
32         enum kobject_action action;
33         struct kobj_uevent_env ku_env;
34         struct list_head elist;
35         char name[DM_NAME_LEN];
36         char uuid[DM_UUID_LEN];
37 };
38
39 static void dm_uevent_free(struct dm_uevent *event)
40 {
41         kmem_cache_free(_dm_event_cache, event);
42 }
43
44 static struct dm_uevent *dm_uevent_alloc(struct mapped_device *md)
45 {
46         struct dm_uevent *event;
47
48         event = kmem_cache_zalloc(_dm_event_cache, GFP_ATOMIC);
49         if (!event)
50                 return NULL;
51
52         INIT_LIST_HEAD(&event->elist);
53         event->md = md;
54
55         return event;
56 }
57
58 static struct dm_uevent *dm_build_path_uevent(struct mapped_device *md,
59                                               struct dm_target *ti,
60                                               enum kobject_action action,
61                                               const char *dm_action,
62                                               const char *path,
63                                               unsigned nr_valid_paths)
64 {
65         struct dm_uevent *event;
66
67         event = dm_uevent_alloc(md);
68         if (!event) {
69                 DMERR("%s: dm_uevent_alloc() failed", __func__);
70                 goto err_nomem;
71         }
72
73         event->action = action;
74
75         if (add_uevent_var(&event->ku_env, "DM_TARGET=%s", ti->type->name)) {
76                 DMERR("%s: add_uevent_var() for DM_TARGET failed",
77                       __func__);
78                 goto err_add;
79         }
80
81         if (add_uevent_var(&event->ku_env, "DM_ACTION=%s", dm_action)) {
82                 DMERR("%s: add_uevent_var() for DM_ACTION failed",
83                       __func__);
84                 goto err_add;
85         }
86
87         if (add_uevent_var(&event->ku_env, "DM_SEQNUM=%u",
88                            dm_next_uevent_seq(md))) {
89                 DMERR("%s: add_uevent_var() for DM_SEQNUM failed",
90                       __func__);
91                 goto err_add;
92         }
93
94         if (add_uevent_var(&event->ku_env, "DM_PATH=%s", path)) {
95                 DMERR("%s: add_uevent_var() for DM_PATH failed", __func__);
96                 goto err_add;
97         }
98
99         if (add_uevent_var(&event->ku_env, "DM_NR_VALID_PATHS=%d",
100                            nr_valid_paths)) {
101                 DMERR("%s: add_uevent_var() for DM_NR_VALID_PATHS failed",
102                       __func__);
103                 goto err_add;
104         }
105
106         return event;
107
108 err_add:
109         dm_uevent_free(event);
110 err_nomem:
111         return ERR_PTR(-ENOMEM);
112 }
113
114 /**
115  * dm_send_uevents - send uevents for given list
116  *
117  * @events:     list of events to send
118  * @kobj:       kobject generating event
119  *
120  */
121 void dm_send_uevents(struct list_head *events, struct kobject *kobj)
122 {
123         int r;
124         struct dm_uevent *event, *next;
125
126         list_for_each_entry_safe(event, next, events, elist) {
127                 list_del_init(&event->elist);
128
129                 /*
130                  * When a device is being removed this copy fails and we
131                  * discard these unsent events.
132                  */
133                 if (dm_copy_name_and_uuid(event->md, event->name,
134                                           event->uuid)) {
135                         DMINFO("%s: skipping sending uevent for lost device",
136                                __func__);
137                         goto uevent_free;
138                 }
139
140                 if (add_uevent_var(&event->ku_env, "DM_NAME=%s", event->name)) {
141                         DMERR("%s: add_uevent_var() for DM_NAME failed",
142                               __func__);
143                         goto uevent_free;
144                 }
145
146                 if (add_uevent_var(&event->ku_env, "DM_UUID=%s", event->uuid)) {
147                         DMERR("%s: add_uevent_var() for DM_UUID failed",
148                               __func__);
149                         goto uevent_free;
150                 }
151
152                 r = kobject_uevent_env(kobj, event->action, event->ku_env.envp);
153                 if (r)
154                         DMERR("%s: kobject_uevent_env failed", __func__);
155 uevent_free:
156                 dm_uevent_free(event);
157         }
158 }
159 EXPORT_SYMBOL_GPL(dm_send_uevents);
160
161 /**
162  * dm_path_uevent - called to create a new path event and queue it
163  *
164  * @event_type: path event type enum
165  * @ti:                 pointer to a dm_target
166  * @path:               string containing pathname
167  * @nr_valid_paths:     number of valid paths remaining
168  *
169  */
170 void dm_path_uevent(enum dm_uevent_type event_type, struct dm_target *ti,
171                    const char *path, unsigned nr_valid_paths)
172 {
173         struct mapped_device *md = dm_table_get_md(ti->table);
174         struct dm_uevent *event;
175
176         if (event_type >= ARRAY_SIZE(_dm_uevent_type_names)) {
177                 DMERR("%s: Invalid event_type %d", __func__, event_type);
178                 return;
179         }
180
181         event = dm_build_path_uevent(md, ti,
182                                      _dm_uevent_type_names[event_type].action,
183                                      _dm_uevent_type_names[event_type].name,
184                                      path, nr_valid_paths);
185         if (IS_ERR(event))
186                 return;
187
188         dm_uevent_add(md, &event->elist);
189 }
190 EXPORT_SYMBOL_GPL(dm_path_uevent);
191
192 int dm_uevent_init(void)
193 {
194         _dm_event_cache = KMEM_CACHE(dm_uevent, 0);
195         if (!_dm_event_cache)
196                 return -ENOMEM;
197
198         DMINFO("version 1.0.3");
199
200         return 0;
201 }
202
203 void dm_uevent_exit(void)
204 {
205         kmem_cache_destroy(_dm_event_cache);
206 }